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Just picked up Yamaha apex snowmobile 150 efi motor for a mini pro 116 just wondering if the hull will take it ? Currently runing a Briggs 35 hp with whirlwind adjustable prop And century 1.62:1 reduction. I think it will work great motor is like 10lbs heaveir than Briggs and like 115 more hp what you guys think ?
First Hi,and welcome .
I'm a newbie too kinda, all very good people.
In my mind you will need more prop or waist half your new hp.
You will need WAY more reduction. Most props cant turn there tips past
the speed of sound. A 54" prop tops out around 3000 rpm.
A 64" is like 2500. Your Yamaha needs to spin like 10,000 rpm to get the HP.
my main question is will hull take that hp and tourqe ? i understand that I'm going to need a gear reduction! I'm going to make my own reduction useing gates hd belts and cogs and have all math done for the re drive. motor max rpm at 10 500 k but has a built in reduction so motor output shaf is about 8500rpm and I'm gona use cogged belt redrive to get perfect prop shaft speed but why would my Briggs prop not work it's a 67 I thinkQuote:
Originally Posted by Coyotes-R-Us
Can't say anything about the hull.
I would think the pitch would be way off.
If you could turn it with 35 hp 110 would be waisted
That's a BIG difference.
It will be fine. Of course you'll need to match the reduction as mentioned. The biggest problem I've seen was altering the exhaust for airboat use. If the exhaust isn't tuned correct the engine won't perform right.
My prop is adjustable whirl wind prop so it should work? and do you think exhaust needs more or less back pressure for airboat use ? I plan on useing a modified hindel exhaust snowmobile exhaust
The prop should work. I don't know about back pressure. All I know is the guy had trouble getting it to run right with an altered exhaust. He put a stock exhaust on it and it ran fine.
your hull would be fine as far as the exhaust you will have to jet the carb for a tuned pipe i am running a 70 hp yamaha piped motor 2.75 belt reduction and spin a 68 in three blade warp drive at 8 deg